In the distribution industry, a packaging material, card, poster, seal or label, which are for display, have been generally and widely used to display a commodity name, commodity content(s), manufacturer's name, selling price, or the like.
In addition, a label is known to be obtained by applying specific treatment to the card for display or the like so that character(s) or pattern(s) appears by discoloration under specific condition, has been known.
Such label is applied to, for example, a campaign label for informing only commodity purchaser about benefit information, a security label (alteration preventive label) capable of discriminating whether a commodity is opened, or the like.
For example, Japanese Patent Kokai Application Publication No. JP2013-210551A (Patent Document 1) proposes a plastic label capable of discoloring an arbitrary area of a label by a simple method that irradiates an uncured coating layer with an energy ray and suitable for a campaign label or a security label.
This plastic label comprises:
a label base material having at least thermal shrinkability and expandability; and
a coating layer formed on at least one surface side of the label base material,
wherein the coating layer is composed of an energy ray curable resin having an energy ray-curable functional group and a weight average molecular weight of 10000 to 100000, and
at least a part of the resin is irradiated with energy rays to be cured and a part cured by the thermal shrinkage and expansion of the label base material is discolored.
In addition, Japanese Patent Kokai Application Publication No. JP2005-122068A (Patent Document 2) proposes an adhesive label for discriminating unsealing, which is used for sealing of various packages, and is capable of discriminating unsealing of a package at a glance when the adhesive label pasted to the package for sealing is cut and unsealed by a sharp edged cutting tool.
This adhesive label for discriminating unsealing, which is used for sealing of the package, is formed of a laminate, having at least a transparent oxygen barrier layer on an outer side, an independent island-like oxygen-detecting agent layer in an intermediate section, an oxygen-absorbing layer, an oxygen barrier layer on an inner side, an adhesive layer disposed on the back side of the oxygen barrier layer, and release paper.
The label is so constituted that, when the tacky adhesive label pasted for sealing the package is cut for the purpose of the unsealing, the independent island-like oxygen-detecting agent layer in the intermediate section is cut simultaneously.